This replaces the "Show question text in the question list?" filter, which was
never really a filter, with a new widget displayed alongside other question bank
controls like "Create a new question" and "Reset columns".
It also refactors the logic of displaying the question text field or not, so that
it is all handled within the qbank_viewquestiontext plugin rather than relying on
code in the view.
Mark Johnson
33e52fe4ed